title: Ferromagnetic interactions in heterobimetallic chains formed through the secondary coordination of dithiolene complexes.
abstract: A novel paramagnetic ( S = 1/2) copper dithiolene complex based on the tfadt ligand (tfadt: 3-trifluoromethyl-acrylonitrile-2,3-dithiolate) is prepared as its n-Bu 4N (+) salt and crystallized with [Ni(cyclam)] (2+) into infinite, one-dimensional chains through CN...Ni interactions, avoiding any direct (antiferromagnetic) overlap between the dithiolene complexes. An unprecedented ferromagnetic interaction within the heterobimetallic chains between the S = 1/2 [Cu(tfadt) 2] (2-) and the S = 1 [Ni(cyclam)] (2+) tectons is observed, despite the fact that the SOMOs of both [Cu(tfadt) 2] (2-) (with d x (2) - y (2) symmetry) and [Ni(cyclam)] (2+) (with d x (2) - y (2) and d z (2) symmetry) have the same e g symmetry. The experimental exchange interaction deduced from the fit of the magnetic susceptibility ( J exp/ k B = +5.0 K) was confirmed by theoretical calculations ( J calc/ k B = +7.3 K), and a rationale is given for the presence of an intrachain ferromagnetic interaction.
authors.affiliation: Université Rennes 1 & CNRS, Sciences Chimiques de Rennes, UMR6226, Bât 10C, Campus de Beaulieu, 35042 Rennes cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Jeannin
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Clérac
authors.forename: Thomas
authors.initials: T
authors.lastname: Cauchy
authors.forename: Marc
authors.initials: M
authors.lastname: Fourmigué
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry; D008280:Magnetics; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; C024560:cyclam; D003300:Copper; D009532:Nickel